Field of the Invention
The present invention relates to foundations for mattresses, and more particularly to foundations made of foam that may be compressed and folded into dimensions more suitable for shipping and storage.
Related Art
Prior art mattress foundations have typically been produced using hard materials like wood and plastic which must be assembled before they are able to support a mattress. These known mattress foundations typically consist of a rectangular frame with a series of slats spanning the width of the rigid frame so that the foundation frame sits on and spans a standard bed frame and a mattress is supported by the slats on the top side of the foundation. Other types of known foundations substitute the series of slats for one or more cross beams or a single sheet of rigid material which may be known as a platform mattress foundation. Additionally, some known mattress foundations combine the rigid frame and cross members with supporting springs and are known as “box springs.” These box springs are designed to provide more ergonomic support as they may flex when certain amounts of force are applied to the supported mattress, but the rigidity of the frame and stiffness of the springs still prevent folding and compression that equates to the compactness of the compressible foam mattress foundation described herein. Some of these mattress foundations with rigid support members can be disassembled for easier storage, shipping, and delivery, but these rigid foundations must then be assembled for use.
Some current mattress foundations include foam as a primary support material for the mattress rather than the rectangular frame with slats as described above. However, these foam foundation assemblies include a rigid panel base that spans the entire area within the periphery of the foam block (lengthwise and crosswise). For example, U.S. Pat. No. 4,106,139 discloses a foam foundation, but the panel base connected to the foundation within the cover is rigid and prevents the foundation from being folded for easier shipping and storage. As seen in US Pat. Pub. No. 2004/0055086, separate foam foundation modules have individual panel bases that are connected together by hinged fasteners that allow the modules to be folded. Although adjacent panel bases are connected together by fasteners, foam blocks in adjacent modules are not connected in order to permit the modules' adjacent panel bases to be folded together at the hinged fasteners without folding the foam blocks. The folded foundation modules can be stored, shipped, and delivered and then unfolded when ready for use. The folding of the modules reduces the length of the packaged foundation which helps in the delivery of each foundation but does not necessarily reduce the volume of space it takes for storing and shipping a large group of foundations.
Although the foldable foam-panel modules disclosed by the '086 application may have an advantage over the unfoldable foam-panel structure disclosed by the '139 patent by helping in the delivery of foam foundations, it also introduces discontinuities in the support of the mattress because of the multiple sections of foam. None of the prior art references consider using a single, unitary foam block for a foundation with multiple separate support beams that are not directly connected to each other but are only connected to each other through their attachment to the unitary foam block. Prior to the present invention, the conventional thoughts in the bedding industry had been that panels should cover the entire surface area within the periphery of the foam block to properly support the foam block and avoid sagging due to lack of some rigid support across the entire lengthwise and crosswise dimensions of the panel. Even in the '139 patent which has a corrugated bottom surface with grooves in the surface which do not contact the panel, the panel or some other structural support spans the entire surface area within the foam block's periphery, lengthwise and crosswise, and provides rigidity to the foundation assembly in both the lengthwise and crosswise dimensions.
It has also been known to compress and fold foam mattresses so that they can be stored, shipped, and delivered in a compact form. However, prior to the present invention, the bedding industry has never been able to both compress and fold foam foundations to the same degree as foam mattresses because the rigid panels or outer rigid framework with interior slats that have traditionally been used for foam foundations had required the rigidity in both the lengthwise and the crosswise dimensions. There has remained a need for a foam foundation that could be folded and compressed to be stored, shipped, and delivered in a compact form and then unfolded and expanded into a usable configuration that provides support to the mattress and has sufficient rigidity spanning the bed frame in either a lengthwise or crosswise dimension to avoid sagging. It would be beneficial to have a compressible foam foundation that does not require a lengthwise and crosswise rigid frame or panels beneath the foam block, or does not require a frame that must be assembled before the foundation can be used.